Turbofan flow path trenches

Abstract

An integrally bladed disk includes a rotor disk and circumferentially spaced first and second blades. The rotor disk has a rim the periphery of which forms a flow surface. The first and second blades extend integrally outward from the rim. The rim defines a trench in the flow surface between the first and second blades aft of a leading edge of the rim. The trench extends axially forward and rearward of a leading edge of the first blade.

The invention claimed is: 
     
       1. An integrally bladed disk, comprising:
 a rotor disk having a rim the periphery of which forms a flow surface; and 
 circumferentially spaced first and second blades extending integrally outward from the rim, wherein a base of each of the first and second blades has a fillet, and wherein the rim defines two or more axially-spaced trenches in the flow surface between the first and second blades aft of a leading edge of the rim, and wherein each trench extends into at least one of the fillets at different axially-spaced locations, and wherein one of the axially-spaced trenches extends axially forward and axially rearward of a leading edge of the first blade. 
 
     
     
       2. The integrally bladed disk of  claim 1 , wherein one of the axially-spaced trenches extends axially to about the trailing edge of the first and second blades. 
     
     
       3. The integrally bladed disk of  claim 1 , wherein each trench has a depth of between about 0.005 inch (0.127 mm) and 0.060 inch (1.52 mm). 
     
     
       4. The integrally bladed disk of  claim 1 , wherein a deepest point of one of the trenches circumferentially aligns with a location of highest stress concentration at a leading edge of the fillet. 
     
     
       5. The integrally bladed disk of  claim 1 , wherein the blades comprise two of a row of blades and a plurality of axially spaced trenches are disposed between each blade in the row. 
     
     
       6. A gas turbine engine having a stress relief feature, the engine comprising:
 an integral rotary body having a blade extending from a fillet in a peripheral rim, wherein the peripheral rim forms a depression that extends into the fillet; 
 wherein the blade is one of a row of blades and a plurality of depressions are disposed between each of the blades in the row. 
 
     
     
       7. The gas turbine engine of  claim 6 , wherein the depression extends axially forward and rearward of a leading edge of the blade. 
     
     
       8. The gas turbine engine of  claim 6 , wherein the depression extends axially to about a trailing edge of the blade. 
     
     
       9. The gas turbine engine of  claim 6 , wherein the depression has a depth of between about 0.005 inch (0.127 mm) and 0.060 inch (1.52 mm). 
     
     
       10. The gas turbine engine of  claim 6 , wherein a deepest point of the depression circumferentially aligns with a location of highest stress concentration at a leading edge of the fillet. 
     
     
       11. An integrally bladed disk, comprising:
 a rotor disk having a rim the periphery of which forms a flow surface; and 
 circumferentially spaced first and second blades integrally joined to the rim, wherein each blade includes a fillet along a base thereof between each blade and the rim, and wherein the rim defines two or more axially-spaced trenches in the flow surface between the first and second blades, and wherein each trench extends into at least one fillet at different axially-spaced locations. 
 
     
     
       12. The integrally bladed disk of  claim 11 , wherein a deepest point of one of the trenches circumferentially aligns with a location of highest stress concentration at a leading edge of at least one of the fillets. 
     
     
       13. The integrally bladed disk of  claim 11 , wherein each trench has a depth of between about 0.005 inch (0.127 mm) and 0.060 inch (1.52 mm). 
     
     
       14. The integrally bladed disk of  claim 11 , wherein one of the axially-spaced trenches extends axially forward and axially rearward of a leading edge of the first blade. 
     
     
       15. The integrally bladed disk of  claim 11 , wherein one of the axially-spaced trenches is disposed completely aft of a leading edge of the rim.